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United States Department of Agriculture

Agricultural Research Service

Research Project: Characterization, Etiology, and Disease Management for Vegetable Crops

Location: Vegetable Research

Title: Molecular characterization and detection of Mexican papita viroid

Authors
item Li, Rugang
item Ling, Kai-Shu

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: June 15, 2013
Publication Date: August 9, 2013
Citation: Li, R., Ling, K. 2013. Molecular characterization and detection of Mexican papita viroid. Phytopathology. 103: S2, 80.

Technical Abstract: Mexican papita viroid (MPVd), in genus Pospiviroid and family Pospiviroidae, was first isolated from wild papita (Solanum cardiophyllum Lindl) plants in 1996. Since 2009, several disease outbreaks on greenhouse tomatoes in Canada and Mexico were shown to be caused by MPVd infection. However, the Koch’s Postulates for MPVd have not been established. In the present study, we engineered infectious cDNA clones using two select MPVd isolates (MX and Mex8). Infectivity of the engineered cDNA constructs were examined by mechanical inoculation of ‘Moneymaker’ tomato plants with their respective in vitro RNA transcripts. After 4 weeks post inoculation, disease symptoms of stunting and leaf chlorosis on the inoculated plants were similar to those in field observation. The presence of MPVd on the inoculated plants was confirmed with real-time reverse transcription polymerase chain reaction (RT-PCR). Additional cloning and sequencing of MPVd-MX and MPVd-Mex8 progeny revealed that MPVd existed in host plants as a mixture of various sequence variants. However, the predominant progeny sequences were identical to their respective parental cDNA clones, which accounted for 81.82% for MPV-MX and 78.79% for MPV-Mex8, respectively. Two species-specific and sensitive molecular detection methods including real-time RT-PCR and reverse transcription loop-mediated isothermal amplification (RT-LAMP) were developed and successfully applied for plant and seed health test.

Last Modified: 7/23/2014